I am not one to allow my cat out of the house- ever. I think that is best for my cats- three girls, all different ages, and I live on a fairly busy road and have dogs about. Very different situation.
I did have a cat decide to up and leave- got out of the house as I was moving. He moved in with a neighbour and she let me know that he had. As he was happy there, I did nothing to change the situation- I was ill at the time and had been trying to find homes for all three of my cats. Oscar (white persian) decided that HE would do the choosing of his next home.
One way that would absolutely guarentee that your kitty comes home is to run right out and get a new kitty. Works EVERY time. Proof? I had been catless for a couple of years. I was finally in a more stable situation and decided that I needed a cat. So I adopted Minou. About a month later, I was asked by the shelter I got Minou from to foster a Mom Cat and kittens. Within a week of Mom Cat and the kits (3 of them- entirely too cute!) moving in, two kitties were abandoned on my doorstep (one still lives with me, the other was placed in a loving catless home). If you want to insure the return of your kitty, simply go get another. But don't say I didn't warn you.
Oh- the third cat in the house is my partner's cat. Of course I hooked up with a cat lover!
Let us know what happens, Shell. I promise, God doesn't give us more than we can handle- even when we think we can't.